| [[Composed-Message-Processor]] |
| = Composed Message Processor |
| |
| The |
| http://www.enterpriseintegrationpatterns.com/MessageRouter.html[Composed |
| Message Processor] from the xref:enterprise-integration-patterns.adoc[EIP patterns] |
| |
| How can you maintain the overall message flow when processing a message consisting of multiple elements, each of which may require different processing? |
| |
| image::eip/DistributionAggregate.gif[image] |
| |
| Use Composed Message Processor to process a composite message. |
| The Composed Message Processor splits the message up, routes the sub-messages to the appropriate destinations |
| and re-aggregates the responses back into a single message. |
| |
| With Camel this pattern is implemented by the xref:split-eip.adoc[Splitter] |
| which has built-in aggregation to re-aggregate the responses back into a single message. |
| |
| == Sample |
| |
| This sample uses the xref:split-eip.adoc[Splitter] as composed message processor to process each splitted message, |
| aggregate and return a combined single response. |
| |
| The route and the code comments below explains how you can use the xref:split-eip.adoc[Splitter] to |
| split each message to sub-message which are processed individuallay and then combined back into |
| a single response message via the custom ``aggregationStrategy` (`MyOrderStategy`), which |
| then are the output of the splitter, that are then further processed at the end of the route. |
| |
| [source,java] |
| ---- |
| // this routes starts from the direct:start endpoint |
| // the body is then splitted based on @ separator |
| // the splitter in Camel supports InOut as well and for that we need |
| // to be able to aggregate what response we need to send back, so we provide our |
| // own strategy with the class MyOrderStrategy. |
| from("direct:start") |
| .split(body().tokenize("@"), new MyOrderStrategy()) |
| // each splitted message is then send to this bean where we can process it |
| .to("bean:MyOrderService?method=handleOrder") |
| // this is important to end the splitter route as we do not want to do more routing |
| // on each splitted message |
| .end() |
| // after we have splitted and handled each message we want to send a single combined |
| // response back to the original caller, so we let this bean build it for us |
| // this bean will receive the result of the aggregate strategy: MyOrderStrategy |
| .to("bean:MyOrderService?method=buildCombinedResponse") |
| ---- |
| |
| == More details |
| |
| See the xref:split-eip.adoc[Splitter] EIP. |
